This invention relates to a machine for forming large round bales of fibrous agricultural crops. More particularly, I provide a latching mechanism which senses the pressure being applied to compress the bale while at the same time holding the bale discharge gate closed.
An application titled "Latching Mechanism for a Round Baler" having Ser. No. 282,548 and assigned to the same assignee is made copending with this one by simultaneous submission.
Many bale forming machines exist which form fibrous agricultural crops into bales that are either twine or wire tied. For example, the U.S. Pat. No. 4,009,653 to Sacht discloses a method for forming large round bales in a machine comprising a cage-like frame having a horizontal axis and a generally cylindrical shaped baling zone. Upwardly extending machine sidewalls form the confining end surfaces of the baling zone. A plurality of serially arranged conveying elements enclose and generally define the circumferential periphery of the baling zone. Thus, the size of the baling chamber remains constant during the bale forming process. To accomplish discharge of a completed bale, the baling chamber is divided into two portions approximately along a vertically extending axis cutting plane. The rear portion of the housing is then configured to swing upward from a hinge point at the top, thereby allowing the bale to be discharged rearward.
The U.S. patent application having Ser. No. 162,372, now U.S. Pat. No. 4,319,446, and assigned to the same assignee as this application discloses bale forming means which differ somewhat from the implementation of Sacht. Two additional rollers are added to support the bottom conveyor belts. As viewed from the side the improved system shows four rollers on which a plurality of laterally spaced belts are trained. The second and third rollers (which are respectively in the forward and aft portions of the conveyor midsection) and the fourth roller (which is at the rear of the machine) are disposed to be generally on the cylindrical periphery of the baling zone. The first roller is in front of and somewhat below the plane containing the axis of the third roller. The Arnold etal, invention improves on Sacht in two ways. First, the vertical dimension of the entrance throat is enlarged. This allows the baler to operate in a heavier stand of hay without becoming clogged. Second, by lowering the placement of the front roller, a pickup reel of smaller diameter can be used. This permits the flow of hay being picked up from the windrow to pass into the baling zone without undergoing abrupt changes in direction. The laterally spaced conveyor belts accept the crop material being passed on from the pickup reel and frictionally engage the crop strands to provide inward directed pressure to carry them into the baling zone.
This invention is shown in conjunction with a baler having a bottom conveyor member for receiving agricultural material which is constructed similar to that disclosed in the U.S. patent application having Ser. No. 162,372. Using this type of bottom conveyor, generally cylindrical bales are formed in a cavity of fixed size. The partially completed bale rotates on a horizontal axis while crop material picked up from a windrow is continuously added to the periphery of the bale. As the baling chamber fills, pressure is exerted on the surrounding enclosure. The enclosure is hinged along the top edge to allow the rear portion to open upwardly to enable discharge of a completed bale. I provide a latch mechanism to hold the opposing faces of the enclosure together until the bale is complete.
With my invention the tailgate is mechanically locked in the closed or baling position by adjustable spring loaded latches, one on each side of the baler. As the baling chamber fills, pressure on the tailgate causes a latch slide to compress a spring. Excursion of the latch slide gradually forces the tailgate to come away from its nesting position by as much as an inch. The movement of the tailgate in response to internal pressure is monitored by mechanical and/or graduated electrical sensors to generate visual and audible indications of the bale forming status. Latch release is interlocked with the hydraulic door cylinder linkage which actuates at the initiation of the bale discharge sequence. With my implementation there are no hydraulic pressure gauges to be monitored and small hydraulic leaks will not effect performance.